This invention relates to a protective sheath adapted to cover a syringe needle after use to preclude inadvertent needle stick puncture wounds.
Hypodermic needles are frequently used to administer medications and anaesthetics to patients or withdraw body fluids therefrom by health care personnel. Conventional hypodermic syringes comprise a cylindrical tube with a flange or laterally projecting finger tabs at one end adapted to be supported by the fingers of the user and an extended construction at the other end provided with a suitable mounting for releasably coupling a hypodermic needle thereto. The end of the tube having the flange is open for receiving a plunger used to draw fluid into the tube or dispense it through the needle. The syringes can be disposable, generally formed of plastic, or reusable and formed of a suitable metal which is sterilizable. Disposable syringes generally are supplied in a peel-a-way blister package with needles obtained separately and also contained in peel-a-way blister packages.
Typically, the needles are supplied with protective caps or sheaths which snugly encapsulate the needle. Once the cap is removed, the needle is exposed and poses the risk of accidental puncture to the user and other health care attendants due to incidental handling or mishandling by such users or attendants. Replacing the cap after usage requires aligning the cap with the needle and telescopically sliding the cap thereon. This procedure requires two hands and the undivided attention of the user in a motionless environment. The chance of accidental finger puncture is greatly enhanced during recapping of a used needle and can be extremely hazardous when the needle was used on an infected patient having a blood borne disease. Recent infection control guidelines discourage the recapping of used needles due to the danger to the other hand holding the cap when approaching the distal or pointed end of the needle. When not recapped, the used, exposed needle becomes a temporary hazard to the health care provider during surgical and dental procedures and routine patient care. For example, syringes with exposed needles are sometimes handed over from one nurse to another and needle destroying apparatus may not be readily convenient.
In light of the hazards posed by dangerously contaminated, exposed syringe needles, many attempts have been made to sheath or otherwise cover such used needles to reduce the hazards of accidental needle stick. While such known sheathed syringes have served the purposes for which they were intended, they have not been entirely satisfactory for several reasons. For example, certain ones of these prior known devices do not positively retain or lock the sheath in the extended needle protective position. Others include a complicated design of many parts making the devices relatively expensive and difficult to manufacture. As far as can be ascertained, all known sheathed syringe assemblies require the user to employ both hands to extend the sheath into the extended, needle protective position.